Shock Wave Therapy and Achilles Tendon

SHOCK WAVE THERAPY AND ACHILLES TENDINOPATHY

What is Achilles tendinopathy?

Achilles tendinopathy is a degenerative condition of the calcaneal tendon, the largest and most heavily loaded tendon in the human body. It presents as progressive pain at the back of the ankle, aggravated by physical activity and relieved by rest. It is a common condition among runners but also affects non-athletic patients.

Two main forms are distinguished:

• Mid-portion (corporeal) tendinopathy: affecting the middle portion of the tendon, 2 to 6 cm above the calcaneal insertion. This is the most common form, often characterised by a fusiform thickening of the tendon.
• Insertional tendinopathy: affecting the tendon at its insertion on the calcaneus. It may be accompanied by an enthesopathic calcification (posterior calcaneal spur) and retrocalcaneal bursitis.

Consultations take place at the clinic located at 9 Rue du Regard, 75006 Paris, in the 6th arrondissement.

WHY DOES ACHILLES TENDINOPATHY BECOME CHRONIC?

The Achilles tendon is subjected to considerable mechanical loads: up to 6 to 8 times body weight during running. When the applied load repeatedly exceeds the tendon's capacity to adapt, a degenerative process develops. Histological studies show disorganisation of collagen fibres, pathological neovascularisation and an increase in ground substance (tendinosis).

This degenerative process differs from classical inflammation, which explains why anti-inflammatory medications have limited efficacy and why the condition tends to persist if the mechanical load is not appropriately managed.

MECHANISM OF ACTION OF SHOCK WAVES ON THE ACHILLES TENDON

Radial shock waves act on the degenerative tendon through several complementary pathways:

• Stimulation of neovascularisation: the acoustic waves promote the formation of new blood vessels within the tendon, improving the supply of oxygen and growth factors required for tissue repair.
• Activation of collagen synthesis: the mechanical stimulation of the tendon promotes the production of type I collagen, which is essential for restructuring the tendon matrix.
• Pain modulation: shock waves act on nociceptive nerve endings and contribute to reducing pain perception.
• Regression of pathological neovascularisation: the abnormal neo-vessels associated with chronic pain can be targeted by the shock waves, promoting a more organised tissue restructuring.

TREATMENT PROTOCOL

The protocol generally consists of 3 to 5 sessions, spaced 7 to 10 days apart. Each session lasts approximately 5 to 10 minutes. The painful area is located by palpation and the intensity is gradually adjusted according to the patient's tolerance.

Shock wave therapy is indicated when the tendinopathy has persisted for more than 3 months despite relative rest, training load adaptation and rehabilitation exercises. It may be combined with an eccentric exercise programme.

COMBINATION WITH ECCENTRIC EXERCISES

The Alfredson protocol (eccentric exercises for the triceps surae) is one of the best-documented approaches for mid-portion Achilles tendinopathy. It consists of controlled lowering exercises performed on the edge of a step, carried out daily for 12 weeks.

Combining shock wave therapy with eccentric exercises may provide a greater benefit than either treatment alone. Shock waves stimulate tissue repair at the cellular level, while eccentric exercises optimise the organisation of collagen fibres in response to mechanical loading.

ASSOCIATED OSTEOPATHIC APPROACH

Achilles tendinopathy often occurs within a broader biomechanical context. The osteopathic assessment helps identify contributing factors:

• Ankle mobility: limited dorsiflexion (often related to tightness of the soleus or gastrocnemius) increases the strain on the Achilles tendon.
• Foot biomechanics: excessive rearfoot pronation, midfoot rigidity, insufficiency of the intrinsic foot muscles.
• Posterior chain: mobility restrictions at the pelvis, hamstrings or lumbar spine can alter load distribution across the lower limb.
• Gait analysis: assessment of running technique and footwear, particularly the drop (heel-to-toe differential).

The combined approach (shock wave therapy, eccentric exercises, osteopathic treatment and load management) provides the most comprehensive management of chronic Achilles tendinopathy.

FREQUENTLY ASKED QUESTIONS

Is shock wave therapy effective for Achilles tendinopathy?

Several studies and meta-analyses have shown that radial shock wave therapy is effective in the treatment of chronic Achilles tendinopathy, particularly the mid-portion form. Results are generally assessed at 3 to 6 months and show significant improvement in pain and function.

Can I run during shock wave treatment for the Achilles tendon?

Running is generally not recommended during the treatment course, especially if it causes pain. A gradual return to running is planned based on clinical progress. Lower-impact activities (cycling, swimming) may be maintained if well tolerated.

How many shock wave sessions are needed to treat an Achilles tendon?

The standard protocol consists of 3 to 5 sessions, spaced 7 to 10 days apart. The biological effects continue for several weeks after the final session, and maximum improvement may be observed 3 to 6 months later.

References

• Mani-Babu S, Morrissey D, Waugh C, Screen H, Barton C. (2015). The effectiveness of extracorporeal shock wave therapy in lower limb tendinopathy: a systematic review. The American Journal of Sports Medicine, 43(3):752-761. PMID 24817008
• Rompe JD, Nafe B, Furia JP, Maffulli N. (2007). Eccentric loading versus eccentric loading plus shock-wave treatment for midportion Achilles tendinopathy: a randomized controlled trial. The American Journal of Sports Medicine, 35(10):1659-1667. PMID 17609527